Complex esters are a widely known class of compounds. These materials are esters that are the reaction product of polyhydroxy alcohols (like pentaerythritol, dipentaerythritol, trimethylolpropane and the like) reacted with a mono-acid. These materials are not polyesters, but rather complex esters in that there are several ester groups on anon-polymeric backbone.
U.S. Pat. No. 5,744,626 to O'Lenick teaches “The present invention deals with novel, highly branched complex esters. The compounds are complex esters of multi hydroxy compounds like pentaerythritol reacted with guerbet acids. The introduction of the regiospecific branched guerbet acid portion of the molecule into the compounds of the present invention results in improved liquidity and mold release in polycarbonate applications. As will become clear, we refer to the esters of the present invention as complex esters since the hydroxy compound used in the synthesis contains several hydroxyl groups, placed close to each other, resulting in branching in the ester, and the guerbet acid is itself branched in a very regiospecific beta branch.
U.S. Pat. No. 6,160,144 is directed to trimethylol propane esters that are fatty acid mixtures with an oleic acid content of 85 wt % and a stearic acid content of 0.5 to 2.5 wt %, both relative to the mixture, b) alcohols and c) as desired, polyfunctional carboxylic acids. The invention also relates to hydraulic oils based on these esters, and to the use of the esters as lubricants, as hydraulic oils and in cosmetics.
U.S. Pat. No. 5,486,302 teaches “A lubricant composition of suitable viscosity miscible non-chlorinated, fluorinated hydrocarbon refrigerants includes polyhydric alcohol esters, such as TMP, mono and/or di-pentaerythritol esters, made with branched carboxylic acids.” None of these references either anticipate not make obvious the esters of the present invention.
Until the compounds of the present invention, complex esters that contain both high melting groups (not naturally occurring) and lower melting point groups in the same molecule. The placement of these groups in the same molecule as will become clear from reading the specification of this invention, results in a unique ability to alter a combination of properties, including hardness, rehology and skin aesthetics. It is very important to note that each of the hydroxyl groups on the polyol are randomly either have a high melting or low melting group thereon. This is a direct consequence of the fact that from a reactivity point of view each hydroxyl group is as reactive as each other on the polyol (no regiospecificity) and each carboxyl on each acid is equally reactive, resulting in a totally random complex ester. This is the exact opposite of what happens in nature, where each group is carefully controlled using enzyme systems possessed by the living plant or animal making such esters biologically. This random pattern is critical to the functionality making the resulting mixed ester very unlikely to form highly organized crystalline waxes, rather forming amphorous solids and butter like products. We have determined that the difference in melting point of at least 20° C. is a critical factor in the present invention. When the range of melt point is this far apart (i.e. the difference between the high melting point acid and the low melting point acid,) the resulting product has a softness that confers a butter like consistency. Without wanting to be held to one particular explanation, we believe that when the difference is that great a fractional solidification occurs upon cooling resulting in an appreciable amount of time where there are both solid and liquid domains in the cooling wax. This lack of uniformity results in the “disrupted wax” being formed. In a preferred embodiment, the lower melting acid is liquid at ambient temperature and never becomes solid under ambient temperatures, which is the temperature of application for personal care products.
Until the compounds of the present invention, complex esters that contain both high melting groups (not naturally occurring) and lower melting point groups in the same molecule. The placement of these groups in the same molecule as will become clear from reading the specification of this invention, results in a unique ability to alter a combination of properties, including hardness, rehology and skin aesthetics.